"I think that issue has been resolved," Durbin told my colleague Manu Raju on Saturday. "I think it's necessary to include the langauge. The reason is that we hope at the end of the day ... to still work out an agremeent and the bureau of prisons so they will buy this Thompson prison which has been sitting vacant for so many years."

Last December, the Obama Administration proposed buying the Thompson, Ill., prison from the state. The facility would have housed war-on-terror detainees currently being held indefinitely at Guantanamo and might have also hosted military commission trials. However, those ideas encountered stiff opposition from many Republicans and some Democrats.

Durbin has since settled on a fallback proposal to have the Justice Department buy the prison solely for use by ordinary federal prisoners. The Obama administration planned to pay $170 million for the prison. The House voted to approve $95 million for the purchase last week as part of a full-year continuing budget resolution. That measure has stalled in the Senate, but Durbin said he still wants funding to buy the prison — at least as a first step.

"It won't go through unless that language clearly says Guantanamo detainees cannot be sent there," Durbin told POLITICO. "I supported president's position on that initially — that issue has been resolved politically, and this bill, the language in it, reflects the political reality."

Spokesmen for the Justice Department and the White House had no comment Saturday when asked if the administration was lobbying the Senate to drop the civilian-trial-and-transfer ban language in the defense bill. The provision bans the transfer of Guantanamo prisoners to the U.S. for any reason, including criminal trial. As a result, the administration's only likely options would be military commission trials at Guantanamo — which the Obama team has pursued in a handful of cases — or forgoing trials altogether. Another rider in the defense bill limits transfers abroad and could restrict or eliminate Obama's ability to shrink the head count, which stands at 174.